Coyote gen 2 PCM shutdown problem

[Mike Ushba]

Hello everyone! I need advice about Coyote gen2 wiring. I swapped gen2 to mustang s197. So what’s the problem - now engine starts only through a direct wire from the ignition switch to the starter relay (the start signal did not come to the PCM, but directly to the relay). It may sound strange, but it works. if connected according to the factory wiring diagram, the PCM does not respond to the start signal on pin 42 and does not close the starter relay. I don’t know why🤷🏻*♂️🤷🏻*♂️ BUT, the most important question is turning off the engine. I turn off the ignition switch, the signal goes from pins 64 and 65. but the PCM continues to supply ground through pin 20 to the PCM relay... therefore, the PCM remains actively supplied with power on pins 99 and 97. PCM does not go to sleep, power continues to flow, including to MAF, it heats up and stops working. You can only turn off the PCM by disconnecting the connector from the battery.


any help would be appreciated

[michael everson]

I am slightly confused. Are you now running a GEN 2 coyote or the S197 engine? I have never had any issues wiring a coyote regardless of which version using the ford control pack. Are you using a control pack?
Mike

[Mike Ushba]

I have gen2 Coyote engine in 13’ Mustang. I didn't use control pack, I upgraded my Mustang's wiring so that it would fit the engine's PCM and removed PATS from the PCM programmatically.

[edwardb]

Almost everyone here uses the Ford Performance control pack. So not sure how much experience or recommendations you'll get. I've done two Coyote installations and about to do a third. So some knowledge/experience. But only with the control packs. Can't help you with the codes you're getting. Haven't seen them.

[Mbufford]

The old PCM will not operate that coyote properly—you either need the ‘15-‘17 ECM, or go aftermarket.

I’m using the Holley Terminator X on my Gen2 Coyote, and it’s very straightforward to install the wiring—everything is labeled for you.

I also just installed the new Bluetooth module that lets me tune from my phone or iPad. Or, you can stick with the included touchscreen control module. Either way, great system that is easy to use, tune, and operate—and it has a self-learning tune function, which is awesome.

Pretty pricey system at $3k, but if you wait for a sale, it gets better. I got 20% off on the after-Thanksgiving sale. May be able to get a discount this weekend…

[Mike Ushba]

The old PCM will not operate that coyote properly—you either need the ‘15-‘17 ECM, or go aftermarket.

I’m using the Holley Terminator X on my Gen2 Coyote, and it’s very straightforward to install the wiring—everything is labeled for you.

I also just installed the new Bluetooth module that lets me tune from my phone or iPad. Or, you can stick with the included touchscreen control module. Either way, great system that is easy to use, tune, and operate—and it has a self-learning tune function, which is awesome.

Pretty pricey system at $3k, but if you wait for a sale, it gets better. I got 20% off on the after-Thanksgiving sale. May be able to get a discount this weekend…

I have a PCM from this engine. I just changed the wiring for 2 connectors (the 2013 PCM has 3 of them). Now the engine works as it should (MAF indicators, fuel map adjustments, A/F and other indicators are normal).
but there is a problem described in the tread…

[Mbufford]

But you’re using the 2013 harness, right? Without having my hands on it with schematics for both the 2013 harness and the 2015-17 ECU pinouts, I can only assume something is not wired correctly.

If it were me, I would isolate the starter circuit and build one separately on the bench with a basic relay. That’s what I did with my roadster, since I kind of had to hack the RF and Terminator harnesses to work together.

It sounds like you have the schematics for the 2015-17 ECU pinouts. If you also have the 2013 harness schematic, try posting them both so we can try and help figure out where the gremlin is hiding.

[Mike Ushba]

But you’re using the 2013 harness, right? Without having my hands on it with schematics for both the 2013 harness and the 2015-17 ECU pinouts, I can only assume something is not wired correctly.

If it were me, I would isolate the starter circuit and build one separately on the bench with a basic relay. That’s what I did with my roadster, since I kind of had to hack the RF and Terminator harnesses to work together.

It sounds like you have the schematics for the 2015-17 ECU pinouts. If you also have the 2013 harness schematic, try posting them both so we can try and help figure out where the gremlin is hiding.

This is for 2013 https://iihs.net/fsm/?d=711
Here are for 2017 https://chipford.ru/wiring-diagrams-ford-mustang-2015.html

Now I’m hot sure about 49 pin of c175b (ies), is this + from pcm to bcm, or -, or signal from bcm to pcm. Now it just disconnected, maybe maybe the reason is in this pin, I need to look

[Mike Ushba]

This is for 2013 https://iihs.net/fsm/?d=711
Here are for 2017 https://chipford.ru/wiring-diagrams-ford-mustang-2015.html

Now I’m hot sure about 49 pin of c175b (ies), is this + from pcm to bcm, or -, or signal from bcm to pcm. Now it just disconnected, maybe maybe the reason is in this pin, I need to look


Yep… the problem was in pin 49, it must be “hot when start and run”. How it ok, pcm shut down after 5-7 sec after ignition turn off.